Not all cars do this, german car feature? (only VW's I've driven from 2000's onward seemed to have)

In those cases, you just hold the signal to the point of switch activation, then let go when done.

I think "comfort turn signal" is a feature all newer (2000+) cars should have. I haven't found one from that age that didn't have this feature.

2002 Mazda Miata and 2002 Toyota Camry XLE don't have this. I couldn't find anything about it being a regulation, seems to have become common toward end of that decade though.

I've had this feature in Chrysler, Ford, Honda, and Hyundai cars ranging in year from 1995 to 2021.

Works on my 2009 Honda and 2017 Chrysler.

My 2012 Vauxhall Astra does this.

It's been too long since I posted to edit this, so I'll reply to my own comment: something else my car does that isn't at all unique and some people might be delighted to learn (if theirs supports it too), is that if you hold down the unlock button on the keyfob (rather than press it), it lowers all of the electric windows, and if you hold down the lock button, it raises them. Useful if you left one of your windows open and it starts raining; you don't need to go to the car to shut the windows.

Another German car feature. There's some regulation in the US that requires them to be coded not to go back up (but you can change the coding with a cable). Family has an X5 that will go down as you describe but not up for those reasons.

My Kia has it as well.

Mazda too